After Gwok Jing mastered the 9 Yum Jen Ging, he used the ideas he learned from the manual to modify and improve upon the Hong Lung 18 Palms that his teacher, North Beggar Hung 7 Gung, originally taught to him.
After being injured by West Poison Au Yeung Fung, Hung 7 Gung also studied the 9 Yum Jen Ging to recover his martial arts. Hung 7 Gung's Hong Lung 18 Palms, however, did not change. Why not? Is it just because Hung 7 Gung did not study as much of the 9 Yum Jen Ging as Gwok Jing did?